V1 charts display a small amount of diagnostic metadata such as revision links and 1 trace link in a tooltip.
V2 charts also display a small amount of diagnostic metadata in a tooltip, but should display significantly more.
Users should be able to select multiple revisions in the chart to compare metadata, suggesting a table based on the one in telemetry's results.html:
https://github.com/catapult-project/catapult/blob/master/docs/metrics-results-ui.md

That UI needs to be ported from Polymer 1 with ViewState to Polymer 2 with Redux and undergo a few small design changes.